| Summary: | 碩士 === 長庚大學 === 化工與材料工程學系 === 101 === This study investigated the application of polyvinyl alcohol (PVA)/ carbon nano-tubes (CNTs) composite in alkaline direct ethanol fuel cell (ADEFC) application. This composite polymeric membrane was examined for ethanol permeability, alkaline uptake, and ionic conductivity of the potassium hydroxide (KOH)-doped electrolytes. Besides, these electrolytes were manufactured into membrane electrode assemblies (MEA) and the resulting fuel cell performance was measured by feeding ethanol/KOH solutions.
The effects of CNT addition, KOH concentration, operating temperature, ethanol concentration, anode flow rate, and cathode oxygen feed flow rate on the performance of ADEFCs were studied. It was found that by adding carbon nano-tubes (CNTs) into the PVA matrix, the alkaline uptake and the ionic conductivity of the KOH-doped electrolyte were increased. Meanwhile, the CNT-containing membrane exhibited a lower swelling ratio and suppressed ethanol permeability than the pristine PVA film. Among the studied operating parameters, cell temperature had the highest impact on the cell performance. As the temperature was raised from 30 to 60C, the peak power density increased from 32.8 to 65.2 mW cm-2, a 99 % increase. The optimal condition for the ADEFC was found to be operated at an anode feed of 3 M ethanol in 5 M KOH solution (at a flow rate of 5 cm3 min-1), cathode feed of moisturized oxygen (with a flow rate of 100 cm3 min-1), at a temperature of 60C, and with the PVA/CNT/KOH electrolyte. Therefore, the PVA/CNT/KOH electrolyte is a suitable l solid electrolyte for ADEFCs and has potential for commercialization in alkaline fuel cell applications.
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